Deadly Ecosystem ... In Your Pillow

The typical pillow contains more than a million fungal spores, researchers found. That's several thousand spores for every little gram of material.

There's more.

Other studies have shown pillows and other bedding harbor dust mites, microscopic spider-like creatures that feed on flakes of human skin (see picture at top of page).

"We know that pillows are inhabited by the house dust mite which eats fungi, and one theory is that the fungi are in turn using the house dust mites' feces as a major source of nitrogen and nutrition (along with human skin scales)," says study leader Ashley Woodcock at the University of Manchester. "There could therefore be a 'miniature ecosystem' at work inside our pillows."

All pillows

Woodcock and her colleagues examined feather and synthetic pillows that had been in use from 1.5 years to 20 years.

The most common fungi found is called aspergillus fumigatus, which is also the most likely to cause disease, the researchers say. It is in fact the leading infectious cause of death in leukemia and bone marrow transplant patients.

Fungi also exacerbate asthma.

Synthetic pillows carried more fungi, the study concluded. Other species uncovered include fungi normally found in bread and in showers.

The results are detailed today in the journal Allergy. The study is not the first to point out the problem.

Research in 2000 by the National Institute of Environmental Health Sciences (NIEHS) concluded that 22 million U.S. homes had bedding with dust mite allergen concentrations exceeding a level thought to trigger asthma symptoms.

What to do

Hospitals typically cover pillows in plastic. But when patients go home, often with weakened immune systems, their own pillows may pose a risk of infection, the scientists said.

"These new findings are potentially of major significance to people with allergic diseases of the lungs and damaged immune systems - especially those being sent home from hospital," said Geoffrey Scott, Chairman of the Fungal Research Trust which funded the study.

You can take action. The NIEHS suggests:

Put allergen-impermeable covers on pillows and mattresses.

Wash bedding at least weekly in hot water.

Vacuum carpets regularly and steam clean periodically.

If all this doesn't disgust you, consider one final thought: In a separate study this year, scientists found evidence that aspergillus fumigatus is having sex, an act thought not possible among fungi.

Rob was a writer and editor at Space.com starting in 1999. He served as managing editor of Live Science at its launch in 2004. He is now Chief Content Officer overseeing media properties for the sites’ parent company, Purch. Prior to joining the company, Rob was an editor at The Star-Ledger in New Jersey, and in 1998 he was founder and editor of the science news website ExploreZone. He has a journalism degree from Humboldt State University in California.